FOCUSED POWER TRANSFER FOR IMPLANTABLE MEDICAL DEVICE

• US 20170025888A1
• Filed: 07/18/2016
• Published: 01/26/2017
• Est. Priority Date: 07/23/2015
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: O'Brien, Richard J, Cinbis, Can
• Granted Patent: US 10,355,512 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/3758 Packaging of the components within the casing
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A rechargeable cell of an implantable medical device is recharged by an external charging unit that includes a transmitting coil configured to emit an electromagnetic field and a near-field focusing plate having a subwavelength structure pattern that focuses the emitted electromagnetic field to a focal pattern. The implantable medical device includes a housing having a window of an electromagnetically transparent material and a receiving coil enclosed by the housing. The receiving coil extends adjacent to and is aligned with the window. The rechargeable cell is enclosed by the housing and is configured to be charged by current induced in the receiving coil when the receiving coil is exposed to the focal pattern. In some examples, the near-field focusing plate is configured to produce the focal pattern to have a size that is less than an outer dimension of the window and a focal length from the near-field focusing plate that at least reaches the window.

Claims

1. An implantable medical device, comprising:

a housing comprising a first window having an outer dimension, the first window comprising an electromagnetically transparent material;

a receiving coil enclosed by the housing, the receiving coil extending adjacent to and aligned with the first window;

a rechargeable cell configured to be charged by the receiving coil when the receiving coil is exposed to a subwavelength focused electromagnetic field that traverses the first window with a focal pattern size that is less than the window outer dimension.

2. The device of claim 1, wherein the housing has a major length and the first window outer dimension is equal to or less than half of the major length.

3. The device of claim 1, further comprising:

a near-field focusing plate adjacent the receiving coil and comprising subwavelength structures for re-focusing electromagnetic energy entering the housing.

4. The device of claim 3, further comprising:

a second window comprising an electromagnetically transparent material,

wherein the housing comprises a first side and a second side opposing the first side, the first window extending along the first side and the second window extending along the second side in opposition to the first window, the near-field focusing plate configured to re-focus the electromagnetic energy toward the second window.

5. The device of claim 4, wherein:

the second window has an outer dimension; and

the near-field focusing plate comprises subwavelength structures for producing a focal pattern size that is less than the outer dimension of the second window.

6. The device of claim 4, wherein:

the near-field focusing plate and the second window are spaced apart by a distance, and

the near-field focusing plate is configured to re-focus the electromagnetic energy entering the housing at a focal length that is at least the distance between the near-field focusing plate and the second window.

7. The device of claim 1, wherein the housing comprises a conductive metal and the first window is a discrete window extending along an opening in the conductive metal.

8. The device of claim 1, wherein the housing comprises a conductive metal defining a first portion of the housing and an electromagnetically transparent material defining a second portion of the housing, the second portion defining the first window.

9. The device of claim 1, further comprising:

a signal generator powered by the rechargeable cell; and

a control module configured to control the signal generator to deliver an electrical stimulation therapy to a patient.

10. The device of claim 1, further comprising:

a sensing module coupled to a physiological sensor for sensing a physiological signal of a patient, the sensing module powered by the rechargeable cell.

11. The device of claim 1, wherein the housing comprises:

a first side;

a second side opposite the first side,

a sidewall separating the first side and the second side, and

a second magnetically transparent window,

the first window extending along the first side and the second window extending along the second side opposite the first window,

the receiving coil being between the first window and the second window.

12. The device of claim 1, wherein the receiving coil has an inner diameter that is at least equal to the first window outer dimension.

13. The device of claim 1, further comprising a high impedance load configured to generate a potential signal in response to a current induced in the receiving coil, the potential signal triggering the device to perform a function.

14. The device of claim 13, further comprising at least one of:

a signal generator triggered by the potential signal to deliver a therapeutic stimulation pulse;

a sensing module triggered by the potential signal to acquire a physiological signal; and

a telemetry module triggered by the potential signal to establish a bidirectional communication session with another medical device.

15. The device of claim 14, wherein the trigger signal controls a time at which the function is performed and supplies at least a portion of electrical power required to perform the function.

16. An implantable medical device system, comprising:

an external charging unit comprising;

a power transfer control module configured to be coupled to an external power source;

a transmitting coil configured to receive a drive signal from the power transfer control module and emit an electromagnetic field in response to the drive signal;

a first near-field focusing plate comprising a subwavelength structure pattern that focuses the emitted electromagnetic field to a focal pattern; and

an implantable medical device configured to deliver a therapy to a patient or sense a physiological signal of the patient, comprising;

a housing comprising a first window having an outer dimension, the first window comprising an electromagnetically transparent material;

a receiving coil enclosed by the housing, the receiving coil extending adjacent to and aligned with the first window;

a rechargeable cell configured to be charged by the receiving coil when the receiving coil is exposed to the focal pattern through the first window,

the first near-field focusing plate configured to produce the focal pattern to have a size that is less than the first window outer dimension.

17. The system of claim 16, wherein the housing has a major length and the first window outer dimension is equal to or less than half of the major length.

18. The system of claim 16, further comprising:

a second near-field focusing plate enclosed by the housing, the second near-field focusing plate adjacent the receiving coil and comprising subwavelength structures for re-focusing electromagnetic energy entering the housing.

19. The system of claim 18, further comprising:

a second window comprising an electromagnetically transparent material,

wherein the housing comprises a first side and a second side opposing the first side, the first window extending along the first side and the second window extending along the second side in opposition to the first window, the second near field focusing plate configured to re-focus the electromagnetic energy toward the second window.

20. The system of claim 19, wherein:

the second window has an outer dimension; and

the near-field focusing plate comprises subwavelength structures for producing a second focal pattern size that is less than the outer dimension of the second window.

21. The system of claim 19, wherein:

the second near-field focusing plate and the second window are spaced apart by a distance, and

the second near-field focusing plate is configured to re-focus the electromagnetic energy entering the housing at a focal length that is at least the distance between the second near-field focusing plate and the second window.

22. The system of claim 16, wherein the housing comprises a conductive metal and the first window is a discrete window extending along an opening in the conductive metal.

23. The system of claim 16, wherein the housing comprises a conductive metal defining a first portion of the housing and an electromagnetically transparent material defining a second portion of the housing, the second portion defining the first window.

24. The system of claim 16, wherein the first near-field focusing plate comprises a surface reactance that produces the focal pattern at a focal length from the near-field plate that is at least an expected distance from the near-field focusing plate to the first window when the implantable medical device is implanted in the patient.

25. The system of claim 16, further comprising:

a signal generator enclosed by the housing and powered by the rechargeable cell; and

a control module configured to control the signal generator to deliver an electrical stimulation therapy to the patient.

26. The system of claim 16, further comprising:

a sensing module enclosed by the housing and coupled to a physiological sensor for sensing a physiological signal of the patient, the sensing module powered by the rechargeable cell.

27. The system of claim 16, wherein the housing comprises:

a first side;

a second side opposite the first side,

a sidewall separating the first side and the second side,

a first window comprising the magnetically transparent material and extending along one of the first side, second side and the sidewall; and

a second window comprising the magnetically transparent window extending in opposition to the first window along an opposing portion of one of the first side, second side and sidewall,

the receiving coil being between the first window and the second window.

28. The system of claim 16, wherein the receiving coil has an inner diameter that is at least equal to the first window outer dimension.

29. The system of claim 16, wherein the first implantable medical device comprises a high impedance load configured to generate a potential signal in response to a current induced in the receiving coil, the potential signal triggering the first implantable medical device to perform a function.

30. The system of claim 29, wherein the first implantable medical device includes at least one of:

a signal generator triggered by the potential signal to deliver a therapeutic stimulation pulse;

a sensing module triggered by the potential signal to acquire a physiological signal; and

a telemetry module triggered by the potential signal to establish a bidirectional communication session with another medical device.

31. The system of claim 30, wherein the trigger signal controls a time at which the function is performed and supplies at least a portion of electrical power required to perform the function.

32. The system of claim 16, further comprising a second implantable medical device comprising:

a repeater coil;

a housing enclosing the repeater coil, the housing comprising;

a first side comprising a magnetically transparent material adjacent the repeater coil,

a second side opposite the first side and comprising the magnetically transparent material adjacent the repeater coil, the repeater coil being between the magnetically transparent material of the first side and the second side, and

a third near-field focusing plate adjacent to the repeater coil,

the repeater coil extending within a first focal plane when the second implantable medical device is implanted and the first near-field focusing plate focuses the emitted electromagnetic field to the focal pattern,

the third near-field focusing plate configured to focus the emitted electromagnetic field along a second focal plane, the receiving coil extending along the second focal plane when the first implantable medical device and the second implantable medical device are implanted in the patient.

33. The system of claim 16, wherein the transmitting coil comprises a plurality of coils having different focal directions.

34. The system of claim 16, wherein the first near-field focusing plate comprises multiple focusing plates.

35. The system of claim 16, wherein the power transfer and control module is configured to electronically select structures of the first near-field to control the focal pattern and a focal length of the focal pattern.

36. An implantable medical device system comprising:

a first implantable medical device comprising;

a housing comprising a magnetically transparent material;

a receiving coil enclosed by the housing; and

at least one of a therapy delivery module and sensing module;

a second medical device comprising;

a transmitting coil;

a near-field focusing plate configured to focus a near-field electromagnetic field along a focal plane comprising the receiving coil;

the at least one of the therapy delivery module and the sensing module configured to perform a therapy delivery or a sensing operation, respectively, in response to a current induced in the receiving coil by the focused near-field electromagnetic field.